Process for rendering wool unshrinkable



Patented Oct. 4, 1938 I UN HRINKABLE PROCESS F%R RENDERING WOOL Ernest Lee Jackson, Washington, D. O.

No Drawing.

Application November 12, 1929,

Serial No. 406,729

Claims.

(Granted under the act of March 3,1883, as amended April 30, 1928; 370 O. G. 757) This invention described herein may be manufactured and used by or for the Government for Government purposes, without the payment to me of any royalty thereon.

5 This invention relates in general to chlorination processes and'more particularly has reference to a process for rendering wool unshrinkable.

It will be understood that in using the term l0 unshrinkable, non-shrinkable is implied, that is, the process forming the subject matter of the present invention is directed to remedying the disadvantageous characteristic of wool, of shrinking when subjected to washing.

Previous to this time the processes generally followed for treating the wool to prevent the shrinking thereof when subjected to washing have involved the chlorination of the same in an aqueous medium. Among the materials more commonly employed for chlorinating wool in processes of this character have been acidified bleaching powder and hypochlorous acid solutions.

' These treatments heretofore practiced have been attended with numerous disadvantages, the foremost among which is that the sameusually causes damage to the wool under treatment. When, for example, wool is treated with an aqueous solution of bleaching powder, acidified with strong mineral acids, under the conditions necessary for commercial practice, it is difficult, if not impossible, to avoid the presence of free chlorine in the bath. The presence of free chlorine, as is well-known, causes damage to wool even when very small amounts thereof combine with the same.

- If hypochlorous acid solutions in the absence of free chlorine are employed, better results are obtained than by chlorination with solutions of bleaching powder acidified with strong mineral acids. The preparation of pure hypochlorous solutions, however, requires such exceeding care to avoid the presence of free chlorine, as to render the process embodying the same impractical, and also such solutions are unstable so that there is a, consequent deterioration in the chlorinating characteristics of the same over short time intervals.

Tertiary butyl hypochlorite has also been suggested as a chlorinating agent for rendering wool unshrinkable, but a treatment involving the same is not easily controlled and the reaction extends over a comparatively long time. In addition an excessive quantity of the agent is required for satisfactory results as distinguished from my invention wherein only small amounts of the same after drying, to chlorinating agents in solution are required, as the major portion of such is actually utilized in the chlorinating reaction.

An object of this invention is to provide a process for rendering wool unshrinkable, which may be carried on in a medium other than an 5 aqueous one.

Another object of this invention is to provide a process for rendering wool unshrinkable, in which chlorine may be fixed thereon in either large or small quantities.

Still another object of this invention is to provide a process for rendering wool unshrinkable, in which high percentages of chlorine may be fixed thereon without damaging the same.

A further object of this invention is to pro- 15 vide a process for rendering wool unshrinkable which may be easily controlled and attended with uniform results.

This invention consists in general of subjecting wool to a chlorinating process involving the use of a mixture of a stable hypochlorite and a suitable alcohol to render the same unshrinkable, in which the wool is subjected with normal water content under usual atmospheric conditions or with an inert solvent, washing with a solution of an inert solvent subsequent to chlorinating and may inciude dechlorinating the wool and later washing.

While I have set forth my objects and outlined the essence of my invention, the same consists particularly in the ingredients and steps to be hereinafter'set forth and claimed, in the proper proportions and relations, with the understanding that the several necessary substances 35 and compounds comprising my invention and the steps may be widely varied with respect to proportions and relations, and the process carried out under this condition, the particular process which specified a manner of carrying on the same being described as an example of bringing the invention into practical effect without limiting the improvements to the particular improvements set forth.

It will be apparent that in the chlorination of wool in a process of rendering the same unshrinkable, the amount of chlorine which must be introduced into the wool will vary with the kind of wool under treatment, and the degree of unshrinkability necessary for the use to which the wool is to be later put. The introduction of less than one per cent of chlorine into woolen fabrics is sufiicient to produce unshrinkability of the same when subjected to normal washing at low temperatures. In order to render wool 55 corporate the same in an inert solvent such as r and secondary amyl alcohols.

unshrinkable when washed at high temperatures, however, it is necessary to fix higher percentages of chlorine on the same.

In practicing the process to be hereinafter described, I am able to introduce either small or large percentages of chlorine into wool to suit the requirements for which the cloth is intended without causing damage thereto and so controlling the process that the same is attended by uniform results.

I have found that a mixture of an organic hypochlorite possessing suitable stability and certain alcohols affords an efficient chlorinating agent for permanently fixing any desired percentage of chlorine on wool without causing damage thereto. I have found particularly that tertiary butyl hypochlorite and absolute methyl alcohol may be employed to the best advantage.-

In order to obtain a better control with thereactive agents, I have found it preferable to incarbon tetrachloride.

While I have employed carbon tetrachloride with marked success and although I deem it preferable to employ a mixture of tertiary butyl hypochlorite and absolute methyl alcohol in solution with an inert solvent such as carbon tetrachloride, any other suitable organic hypochlorite having suitable stability such as tertiary amyl hypochlorite may be used and also any primary or secondary alcohol containing from one to five carbon atoms, such as absolute ethyl alcohol, also propyl, primary and secondary butyl and primary The use of ingredients other than those preferred, however, have been found less satisfactory as the pronounced instability of other mixtures and the limited amount of chlorine which can be introduced into the wool by the use of the same lessen the utility of these alcohols.

In practicing my invention I have treated wool containing the-normal water content of the same under usual atmospheric conditions and also dried wool. With the use of wool containing the normal water content under usual atmospheric conditions, the percentages of active chlorine up to four and five-tenths per cent by weight of the wool may be introduced into the same without damage. In chlorinating wool which has been dried, however, such as over phosphorus pentoxide or other eficient desiccating agents, or by heating in a stream of dried air at about 85 C., as high as six per cent of active chlorine may be introduced into the wool without affecting the quality thereof.

The active chlorine may be determined by titration of the iodine liberated by a known weight of the chlorinated wool from an acidified solution of potassium iodide, calculated on the basis of one chlorine atom as equivalent to two iodine atoms. Wool treated in accordance with the process forming the subject matter of my invention may contain the normal water content under usual atmospheric conditions as an adequate amount of chlorine to render the same unshrinkable may be introduced under these conditions.

The actual chlorinating agent in the reaction of tertiary butyl hypochlorite and absolute methyl alcohol with wool is of an entirely different character from that which operates in the chlorination of wool with tertiary butyl hypochlorite alone. When anhydrous tertiary butyl hypochlorite is mixed with absolute methyl alcohol, a violent reaction has been found to occur after a short time interval, and the rate of the chlorinaintroduced into the wool.

tion reaction involving a mixture of tertiary butyl hypochlorite and absolute methyl alcohol proceeds much more rapidly than with the use of tertiary butyl hypochlorite alone.

While I do not wish to limit myself to any explanation of the reaction which occurs when methyl alcohol is mixed with tertiary butyl hypochlorite, I believe that the actual chlorinating agent is methyl hypochlorite, which is believed to be formed according to the following equation:

. (CH3) 3COC1+CH3OH- (CH3) 3COH+ CHaOCl -mersed in a solution of ten cubic centimeters of anhydrous tertiary butyl hypochlorite and eight cubic centimeters of absolute methyl alcohol in three hundred cubic centimeters of carbon tetrachloride at room temperature. The wool should be placed in the chlorinating bath containing three mr cent of tertiary butyl hypochlorite and two and five-tenths per cent of methyl alcohol within a few minutes after mixing the constituents of the solution.

' The time of the reaction may be varied to regulate the amount of chlorine which it is desired to introduce into the wool. For example, in immersing wool in a chlorinating bath of the foregoing character at 23 to 26 C. for eleven minutes, five-tenths per cent of active chlorine may be When the cloth is allowed to remain in the bath for twenty-two minutes at 23 to 27 0., one and two-tenths per cent of active chlorine may be fixed on the wool, while after the same is allowed to remain for thirty-five minutes at the same temperatures, two per cent of active chlorine may be introduced into the Wool without damage thereto.

The amount of active chlorine introduced into the wool may be controlled by varying the relative amounts of tertiary butyl hypochlorite, methyl alcohol and carbon tetrachloride and regulating the time the reaction is allowed to proceed. For example fifteen grams of woolen cloth containing a normal water content under the usual atmospheric conditions may be immersed in a solution of twenty-five cubic centimeters of anhydrous tertiary butyl hypochlorite and twenty cubic centimeters of absolute methyl alcohol in three hundred cubic centimeters of carbon tetrachloride at 20 to 25 C. for ten minutes and three and eight-tenths per cent of active chlorine introduced into the wool Without damaging the same with the seven per cent tertiary butyl hypochlorite and six per cent methyl alcohol. If the reaction is only allowed to proceed for five minutes at 20 to 21 0., one per cent of active chlorine may be fixed on the wool.

The time of the reaction may be further reduced by additionally increasing the concentrations ofthe reactive constituents, and also by decreasing the quantity of solvent and raising the temperature. For example, fifteen grams of woolen cloth containing the normal water content under usual atmospheric conditions may be immersed in a solution of twenty-five cubic centimeters of anhydrous tertiary butyl hypochlorite and twenty cubic centimeters of absolute methylalcohol in two hundredcubic centimeters of carbon tetrachloride at 22 to 29 C. for five minutes. With this ten per cent of tertiary butyl hypochlorite and eight per cent methyl alcohol,

three and three-tenths per cent of active chlorine may be fixed on the wool without affecting the quality thereof.

It will be manifest, however, that the reaction must be controlled within certain limits as if wool containing the normal water content under usual atmospheric conditions is chlorinated to fix percentages of active chlorine on the wool of a higher range than from four to four and. fivetenths per cent, the wool is damaged. For example, if two grams of woolen cloth containing a normal water content under usual atmospheric conditions is immersed in a solution of twenty cubic centimeters of anhydrous tertiary butyl hypochlorite and twenty cubic centimeters of absolute methyl alcohol in three hundred cubic centimeters-of carbon tetrachloride at 22 to 30 C. for thirteenminutes, five and three-tenths per cent of active chlorine is introduced into the wool, but the same is damaged.

If the chlorination process is carried on without the use of a diluent, the reaction proceeds in such a rapid rate that proper control is difficult. For example, when woolen cloth containing the normal water content under usual atmospheric conditions is immersed in a mixture of ten cubic centimeters of anhydrous tertiary butyl hypochlorite and one hundred cubic centimeters of absolute methyl alcohol at 23 to 24 C. for fifteen seconds, one and seven-tenths per cent of active chlorine may be introduced into the wool without damage thereto.

An increase in the concentration of the tertiary butyl hypochlorite increases the rate of chlorination. For example, if wool cloth containing the normal water content under usual atmospheric conditions is immersed in fifty cubic centimeters of anhydrous tertiary butyl hypochlorite and sixty cubic centimeters of absolute methyl alcohol at 23 to 26 C. for fifteen seconds, five and four-tenths per cent of active chlorine may be fixed on the wool with slight damage.

By cooling the chlorinating mixture the rate of the reaction may be retarded to some degree. For example, if woolen cloth containing the normal water content under usual atmospheric conditions is immersed in fifty cubic centimeters of anhydrous tertiary butyl hypochlorite and sixty cubic centimeters of absolute methyl alcohol at 4 to T C. for sixty seconds, four and sixtenths per cent of active chlorine may be introduced into the wool with only slight damage.

. If the wool is dried previous to carrying on the chlorination process, however, a larger amount of chlorine may be fixed on thesame without damage than is possible when the wool contains a normal water content under usual atmospheric conditions. For example, fifteen grams of woolen cloth may be dried in a vacuum desiccator over phosphorus pentoxide for forty-eight hours and immersed in a solution of twenty-five cubic centimeters of anhydrous tertiary butyl hypochlorite and twenty cubic centimeters of absolute methyl alcohol in three hundred cubic centimeters of anhydrous carbon tetrachloride at 32 to 34 C. for forty-five minutes. With this seven per cent of tertiary butyl hypochlorite and six per cent of methyl alcohol, six and eight-tenths per cent of active chlorine may be introduced into the wool without causing any appreciable damage thereto.

After any one of the foregoing chlorlnating reactions has been completed the Wool under treatment is preferably quickly and thoroughly cloth by chlorination with a solution of tertiary butyl hypochlorite and methyl alcohol and carbon tetrachloride is sufiicient to render the ma terial treated unshrinkable under ordinary washing conditions. Where cloth is to be washed under conditions of high temperature it is deemed preferable to fix greater percentages of chlorine thereon so as to render the cloth unshrinkable under these conditions. Where only small'amounts of chlorine are introduced into the wool for rendering the same unshrinkable when normally washed, the dechlorlnating bath may be omitted in many instances.

While I, as previously stated, prefer to carry on my chlorination process with a mixture of tertiary butyl hypochlorite and absolute methyl alcohol, I may substitute other alcohols such, for example, as ethyl alcohol, although I find the use of the same less satisfactory. For example, woolen cloth containing the normal water content under usual atmospheric conditions may be immersed in a solution of twenty-five cubic centimeters of anhydrous tertiary butyl hypochlorite and twenty-five cubic centimeters of absolute ethyl alcohol in three hundred cubic centlmeters of carbon tetrachloride at 21 to 39 C. for fifty-four minutes in this fifty fifty per cent solution, one and four-tenths per cent of active chlorine may be fixed on the wool with only slight damager It will be apparent from the foregoing descrip-- tion that the presence of'small amounts of water in the chlorinating agents is not detrimental to the reaction to any appreciable extent. As water has a tendency to damage wool and in any substantial quantity actually does cause damage with increasing amounts, it is preferred, as previously stated, to employ anhydrous agents, however.

There is accomplished by this invention an improved-process for chlorination of wool to render the same unshrinkable without causing damage thereto by treating with mixtures of suitable a1- cohols and organic hypochlorites possessing the required stability, the process being capable of easy control and variations to meet the requirements for which the wool is intended so as to render the wool unshrinkable under all conditions.

While I have described the preferred embodiment of my invention, I wish it to be understood that I do not confine myself to the precise ingredients and steps herein set forth by way of v sisting of tertiary butyl hypochlorite and tertiary 75 tertiary butyl hypochlorite and absolute methyl alcohol in an inert solvent.

4. A process of rendering wool unshrinkable', comprising subjecting the material containing its normal water content under usual atmospheric conditions, to a treatment involving a mixture of tertiary amyl hypochlorite and absolute methyl alcohol in an inert solvent.

' 5. A process of rendering wool unshrinkable comprising treating the wool with a mixture of a tertiary stable hypochlorite of the group consisting of tertiary butyl hypochlorite and. tertiary amyl hypochlorite, and a primary or secondary alcohol having one to five carbon atoms.

6. A process of rendering wool unshrinkable comprising treating the wool with a mixture of a tertiary hypochlorite of the group consisting of tertiary butyl hypochlorite and tertiary amyl hypochlorite and a primary or secondary alcohol containing one to five carbon atoms in an inert solvent. J r

7. The process as set forth in claim 6 wherein the inert solvent is carbon tetrachloride.

8. The process as set forth in claim 6 wherein the alcohol is absolute methyl alcohol.

9. A process of rendering wool unshrinkable comprising removing substantially all moisture from the wool, treating it with a mixture of a tertiary hypochlorite from the group consisting of tertiary butyl hypochlorite and tertiary amyl hypochlorite and a primary or secondary alcohol containing one to five carbon atoms.

10. The invention as set forth in claim 9 wherein the hypochlorite and alcohol are dissolved in an inert solvent.

ERNEST LEE JACKSON. 

